HDT/Vicat Standard

The Vicat testing instrument consists of a bath with an option to mount measuring heads. A built-in thermostat controls the bath temperature. The thermostat ensures a constant increase of the temperature with the standardized gradient over the entire test sequence.
Not only Vicat but also HDT tests can be performed with the measuring heads by simple mechanical conversion. The measuring heads accept the specimen and measure the puncture by the Vicat needle during Vicat tests or deflection of specimens during HDT tests via the installed digital measuring transducer.
In this configuration the Vicat testing instrument can be operated as a manual testing instrument. This means that you have to record the values of the digital measuring transducer and the temperature sequence manually.
We recommend the PC expansion as an accessory. It includes an interface box, the current testXpert software and the respective communication leads. The PC expansion enables fully automatic evaluation of the test job, printout of a test report as well as operation of the Vicat testing instrument via a PC. Temperature and travel values are recorded and saved together with the test parameters.


Key Advantages and Features

  • Optional external re-cooling device for faster attainment of starting temperature
  • Testing to ISO 306, ASTM D1525, ISO 75 and ASTM D648.

Range of application

  • Determination of heat deflection temperature (HDT)
  • as per ISO 75, Parts 1 to 3, and ASTM D648, Methods A and B, on thermoplastics, hard rubber and fiber-reinforced and filled thermosets.
  • Determination of Vicat softening temperature (VST)
  • of thermoplastics as per ISO 306 and ASTM D1525 .
  • Determination of creep behavior
  • under flexural load

Functions, elements and interfaces

  • built-in microprocessor-controlled electronics for temperature control and measured-value acquisition
  • measured values clearly displayed
  • safety thermostat
  • electronic level-monitoring
  • test control and data acquisition via PC with Zwick Roell Prüfsoftware (2 RS232 interfaces required in PC; 1x for temperature channel, 1x for displacement channel)
  • integrated compensation for heat expansion of measuring stations with PC operation
  • manual lowering of measuring stations
  • manual application of test weights.

Test sequence

As soon as the heat-transfer fluid has reached the starting temperature, the specimens are inserted into the measuring stations and lowered manually into the oil bath. In the next step the test weight specified in the standards is applied manually and the menu-driven test-sequence is started on the PC.

On completion of pre-heating under the influence of force, the displacement signals are zeroed (program-controlled) and the heating of the heat-transfer fluid at the pre-set rate is started. As soon as the required deflection, outer-fiber strain or penetration is attained, the heating is switched off and the test is ended.

Re-cooling of the heat-transfer fluid is started manually or by the PC via a solenoid valve. Specimens can afterwards be removed.

Recooling the heat-transfer liquid

Instrument cooling is via a cooling coil located in the oil-bath. Coolant (water) can be pumped in via a connection located on the left-hand side of the instrument.

Water-cooling is switched on manually, but not before 130°C at the earliest. For faster re-cooling a connection for an external re-cooling unit is available.

Technical Overview

Temperature range up to 300°C

HDT/Vicat with temperature range up to 300°C

Item no.

326030[1] [2]

326032[1] [2]

326036[1] [2]


HDT/Vicat 3-300 S

HDT/Vicat 4-300 S

HDT/Vicat 6-300 S

No. of measuring stations




Temperature range

+20 to +300

+20 to +300

+20 to +300



PC-controlled via solenoid valve

Oil capacity, approx.





Height x width x depth

500 x 440 x 600

500 x 710 x 600

500 x 710 x 600


Weight (without accessories), approx.





  1. Water supply required
  1. Instruments are supplied without heat transfer liquid as standard. The required amount can be ordered from accessories.
  1. Can be increased to 6 measuring stations via retrofit

General technical data



General technical data for HDT/Vicat Standard instruments

Display accuracy at 250 °C



Spatial temperature gradient



Temperature measurement resolution



Temperature sensor

Oil-bath temperature is measured by 1 temperature sensor.

Heating rate

50, 120 or freely adjustable


Displacement measurement with digital measuring transducers:




display accuracy




mains voltage



mains frequency



power rating



water supply, max.



PC interfaces required

  • 1x for temperature channel (RS)
  • 1x for displacement channel (RS)

Specimen data

VST specimen dimensions, max.

10 x 6.5 x 10


HDT specimen dimensions, max.

13 x 15 x 130


HDT spans

64, 100 and 101.6


testXpert III Testing Software